var circles = [];

function setup() {
    createCanvas(500, 500);
}

function draw() {
    background(0);
    if (circles.length < 100) {
        circles.push(new Circle(random(width), random(height)));
    }
    for (var i = 0; i < circles.length; i++) {
        circles[i].grow();
        circles[i].show();
    }
}